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Low-to-moderate altitude (2000–2500 m) training camps are an integral part of many athletes’ training programmes.1 Despite potential positive effects on performance, sojourning at altitude represents an important stress on the human body with transiently increased pulmonary and kidney stress, neuroendocrine dysregulation and immune perturbations.2 This highlights the importance of the careful planning and organisation of altitude training camps, which may be even more critical during the current COVID-19 pandemic.
Preliminary reports suggest that hypoxaemia and inflammation induced by COVID-19 result in heterogenous lung injury and acute respiratory distress syndrome, eventually leading to acute respiratory failure.3 Some authors have also speculated that COVID-19-induced acute respiratory distress syndrome may share some similarities with high-altitude pulmonary oedema.4 Even though COVID-19 is primarily a respiratory disease, it can also negatively affect the cardiovascular system, exposing affected patients to myocarditis or myocardial damage.5 Moreover, COVID-19 may impair renal function as well as the circulatory and the immune system.
As we move towards the gradual resumption of normal life once the COVID-19 emergency subsides, athletes will also seek to resume their regular training.6 With the cancellation or postponement of almost half of the scheduled sporting events in 2020 (eg, the Tokyo Olympics, many of the cycling tours, World Marathon Majors and team-sport competitions around the world), many athletes will look to plan at least one altitude training camp in the next 12–18 months.1 During these altitude training periods, athletes will be required to manage changes in training load and to stay socially close to other athletes. Moreover, athletes will be forced to cope with physiological adaptations to altitude, and hypoxia-induced stress on the pulmonary, cardiovascular, renal and immune systems that may be exacerbated by prior exposure to COVID-19. Altitude training may also lead to greater susceptibility to COVID-19 infection and its sequelae by increasing the level of hypoxaemia and further depressing immune function. 6 7 Thus, specific recommendations for altitude training programming are needed to preserve athletes’ health in this post COVID-19 environment (figure 1).
In our opinion, each athlete should be tested for positivity to COVID-19, followed by a careful medical examination and a complete blood screening (white blood cells, haemoglobin, inflammation markers, iron status). In athletes previously infected with COVID-19 (ie, returning a positive antibody test), medical examination should also evaluate cardiological, pulmonary and systemic sequelae of infection. COVID-19 positive athletes should not engage in any form of altitude training and should remain isolated for at least 14 days after symptoms cease. For athletes that do not test positive to infection and do not show contraindication to exercise training, we suggest assessing cardiorespiratory and metabolic responses to incremental exercise in order to evaluate classical functional indices related to respiratory, cardiovascular and muscular systems. Moreover, it is fundamental to ascertain that arterial blood oxygen saturation responses to maximal exercise fall in a normal range (98%–95%), as previously recommended.1 The addition of exercise testing and/or training sessions with reduced fraction of oxygen may be useful to evaluate individual physiological responses to hypoxia before going to altitude.8
Going to altitude
A slower ascent profile to altitude may be suggested to prevent the onset of high-altitude illnesses.
Athletes should be directed to reduce the time spent in close contact with their teammates during daily activities and training sessions. Workout should be accurately modified, reducing the number of athletes involved (eg, players in small-sided games in team sports) and accurately managing training load. Training volume should increase from 75% to the usual sea-level volume, while gradually increasing intensity from the moderate-to-heavy domain is suggested in order to cope with the reduced training stimulus during the COVID-19 confinement. Classic parameters related to physiological adaptations to altitude should be measured and recorded more frequently than usual during the day. Higher than normal changes in SpO2 and heart rate readings are clear signs of maladaptive response to acute exposure to hypoxia.1 Signs and symptoms related to COVID-19, such as elevated core temperature or loss of taste and/or smell, could be added to the daily screening. Regular assessment of respiratory function by monitoring forced expiratory volume in 1 s and forced vital capacity changes should also be performed twice a week. Athletes reporting abnormal values in reference to previous altitude camps should immediately isolate themselves from others and, after medical evaluation, descend to a lower elevation (or supplemented with oxygen if needed) and return to near sea level if symptoms persist. As suggested by others,9 in the event of minor respiratory illness, the ‘neck check’ rule should not be followed. That is, athletes should not continue to exercise even if their symptoms and clinical signs are only confined to the upper airways; a more prolonged rest period is recommended until these symptoms subside.
Return from altitude
Following return to sea level, a careful monitoring of an athlete’s health, especially the immune system and signs/symptoms related to COVID-19, is advised. Moreover, testing athletes for positivity to COVID-19 is recommended. A progressive reintegration before starting to train with other athletes is also suggested.
In conclusion, in the context of the COVID-19 global health emergency, we suggest adopting specific caution before, during and in return from altitude exposure. In particular, early symptoms of maladaptation to hypoxia, and respiratory problems, should be considered with attention as they can mask COVID-19 symptoms.
Twitter @FabioSarto3, @PorcelliSimone
Contributors GM and SP conceived the article. All authors contributed in writing the article. All authors have commented, revised and approved the article in its final form before submission to the British Journal of Sports Medicine.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.